One Rep Max Calculator
Calculate your estimated one-rep max (1RM) for any lift using multiple proven formulas. Get training weight recommendations for strength, hypertrophy, and endurance based on your 1RM.
Enter the number of reps completed (1-30)
Enter weight and reps to calculate your 1RM
Strength
Heavy weight, low reps for maximum strength gains
Hypertrophy
Moderate weight and reps for muscle growth
Endurance
Lighter weight, high reps for muscular endurance
This calculator provides estimates only. Never attempt a true 1RM without proper warm-up, a spotter, and experience with heavy lifting. Consult a qualified trainer if you're new to strength training.
Why Calculate Your One Rep Max?
Knowing your 1RM is essential for programming effective strength training. It allows you to calculate precise training percentages, track progress over time, and ensure you're lifting at the right intensity for your goals. Rather than testing your actual 1RM (which can be dangerous), this calculator estimates it safely from your submaximal lifts.
Frequently Asked Questions
What is a one-rep max (1RM)?
Your one-rep max is the maximum amount of weight you can lift for a single repetition with proper form. It's a key benchmark for measuring strength progress.
Which formula should I use?
Brzycki is most accurate for lower rep ranges (under 10). Epley is simple and widely used. For higher reps, Mayhew or Wathen may be more accurate. Try multiple formulas and use the average.
How often should I test my 1RM?
Most lifters benefit from retesting every 8-12 weeks as part of a training program. This calculator allows you to estimate without maximal testing, reducing injury risk.
Why are the formulas giving different results?
Each formula was developed from different research studies with different populations. The variation is normal. Use the average or the formula that matches your training style best.
Can I use this for all exercises?
Yes, these formulas work for any resistance exercise. However, they're most accurate for compound movements like squats, bench press, and deadlifts.